Device for positioning the end of an optical fibre in a sleeve

ABSTRACT

A device for positioning the end of an optical fibre (1) in a sleeve (10) includes at least three mutually parallel rods (2, 3, 4, 5) forming a passage between themselves for accommodating the fibre end, one end of the rods being intended for insertion into the sleeve (10). Each rod has two flat surfaces intersecting each other at a long edge, one flat surface of each rod lying against a flat surface of an adjacent rod such that the long edges of the rods extend parallel to, and are distributed around the symmetrical axis of the passage. The rods are mutually displaceable in relation to the symmetrical axis, while the engaging surfaces slide on each other for changing the size of the passage to suit different fibre diameters. The ends of the rods intended for insertion in the sleeve have a third flat surface (11, 12, 13, 14) forming equal angles with the two flat surfaces of the respective rod which is intended to engage against a complemental flat surface in the sleeve (10).

FIELD OF THE INVENTION

The present invention relates to a device for positioning the end of anoptical fibre in a sleeve and includes at least three mutually parallelrods, forming between themselves a passage for receiving the fibre end,one end of the rods being intended for accommodation in the sleeve.

BACKGROUND

Such devices, which can be used for contactors, connection means orauxiliary measuring means for optical fibres, are known fromDE-B2-2757216 and EP-B1-015046, for example. These known devices arecomplicated in their construction, however, and are therefore expensiveto manufacture.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an apparatus of thekind described above that is easy and inexpensive to manufacture, andthat gives a distinct positioning of an optical fibre, irrespective ofthe fibre diameter.

This is achieved by the device in accordance with the invention in whicheach rod has first and second flat surfaces intersecting one anotheralong a longitudinal edge, one flat surface of each rod bearing againsta flat surface of an adjacent rod such that the longitudinal edges ofthe rods extend parallel to and are distributed around the axis ofsymmetry of the passage. The flat surfaces of rods are slidable on oneanother to vary the size of the passage to accommodate fibres ofdifferent diameter. The rods each include a portion inserted into thesleeve which has a third surface forming equal angles with the first andsecond surfaces of the rod. The sleeve has flat surfaces bearingrespectively against corresponding third surfaces of the rods.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING

The invention will now be described in detail below with reference tothe accompanying drawing, in which

FIG. 1 is a perspective view of an embodiment of a device in accordancewith the invention,

FIG. 2 is an end view of the device in FIG. 1, and

FIG. 3 is an end view of a second embodiment of the device in accordancewith the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 illustrates an embodiment of a device in accordance with theinvention for positioning the end of an optical fibre 1 in a sleeve 10.The illustrated embodiment includes four mutually parallel rods 2, 3, 4and 5, between themselves forming a passage accommodating the end of thefibre 1, the sleeve 10 accommodating one end of each rod.

Each of the rods 2-5 has two flat surfaces, and in the illustratedembodiment these surfaces meet one another at right-angles along a longedge 6, 7, 8, and 9, as in FIG. 2. In accordance with the invention, oneof the two flat surfaces on the respective rod engages against one ofthe two flat surfaces on a juxtaposed rod such that the long edges 6-9of the respective rods 2-5 extend parallel to, and distributed aroundthe axis of symmetry of the passage for the fibre 1 formed between therods.

The rods 2-5 are mutually, displaceable in relation to this axis ofsymmetry, while gliding against their mutually engaging surfaces for thepurpose of changing the size of the passage to enable the accommodationof fibres having different diameters.

The fibre and its surrounding rods may be glued to each other to ensurefixation of the rods and the fibre accommodated between them.

To enable the accommodation of the rods in a single sleeve 10 fordifferent diameters of the fibre 1, the ends of the rods 2-5 intendedfor insertion in the sleeve 10 are each formed with a third flat surface11, 12, 13 and 14, which is preferably parallel to the longitudinal edgeof the respective rod, in the present case forming an angle 45° relativeto both flat surfaces intersecting each other at right-angles, each ofwhich engages against its complementary surface on adjacent rods. Theother ends of the rods are formed with a quadratic section in theillustrated embodiment, but may of course be formed in any othersuitable way.

In the embodiment illustrated in FIGS. 1 and 2, the ends of the rods 2-5inserted in the sleeve 10 are formed as identical isosceles right-angletriangles. In this embodiment, the interior walls of the sleeve 10enclose a cavity of substantially quadratic cross-section. To enable theaccommodation in the sleeve of mutually displaced rods for placingfibres of different diameters between the rods, the sleeve is providedwith longitudinal recesses 15, 16, 17 and 18 along the intersectionlines between the mutually perpendicular interior walls. The size of therecesses 15-18 depends on the diameter of the fibre 1 that is to beplaced between the rods 2-5.

An alternative embodiment of the sleeve and the rod ends inserted in itis illustrated in FIG. 3. Here, the sleeve denoted by 10 has a cavity ofpurely quadratic cross-section for accommodating the rod ends. These,rod ends denoted 2', 3', 4' and 5', are chamfered at their sharp cornersin a manner illustrated in FIG. 3, to enable their reception in thesleeve 10' when mutually displaced, thus enabling fibres of differentdiameters to be placed between the rods.

The rod ends inserted in the sleeve naturally do not need to be formedidentically alike, but the advantage in doing this is that the set ofrods may be inserted in the sleeve with optional rotational orientation.

A similar set of rods may be inserted in the other end of the sleeve 10illustrated in FIG. 1, to obtain contact between the fibre 1 and the notillustrated fibre in the other set of rods.

The invention is naturally not confined to the use of four rods, itbeing possible to use three, five or more. In all cases, however, thesum of the angles between both longitudinally intersecting surfaces ofthe respective rods must attain 360°. In the case with three rods, thisangle will thus be 120°, while the angle between the third flat surfaceof the respective rod and each of its other two flat surfaces will be60°.

What is claimed is:
 1. A positioning device for a cylindrical opticalfibre comprising a sleeve and at least three parallel rods engaged insaid sleeve and defining a passageway with a longitudinal axis ofsymmetry for accomodating a cylindrical optical fibre in determinedposition, said rods each having first and second flat surfacesintersecting one another along a longitudinal edge, one flat surface ofeach rod bearing against a flat surface of an adjacent rod such that thelongitudinal edges of the rods extend parallel to and are distributedaround said axis of symmetry of the passageway, said flat surfaces ofsaid rods being slidable on one another to vary the size of saidpassageway for accomodating fibres of different diameter, said rods eachincluding a portion inserted into said sleeve having a third flatsurface forming equal angles with said first and second surfacesthereof, said sleeve having flat surfaces bearing respectively againstcorresponding third flat surfaces of said rods, said third flat surfacesof said rods being slidable on said flat surfaces of said sleeve topermit sliding of said first and second flat surfaces of said rods onone another to vary the size of said passageway.
 2. A positioning deviceas claimed in claim 1 wherein said portion of each rod inserted intosaid sleeve has a polygonal cross-section.
 3. A positioning device asclaimed in claim 2 wherein said flat surfaces in said sleeve form acavity of polygonal cross-section.
 4. A positioning device as claimed inclaim 3 wherein said sleeve is provided with longitudinal recesses ateach of the corners of said cavity formed by said flat surfaces in thesleeves.
 5. A positioning device as claimed in claim 3 wherein saidportions of said rods which are inserted into said sleeve are eachchamfered at the intersection of said third surface with the first andsecond surfaces of said rod.
 6. A positioning device as claimed in claim3 wherein said portions of said rods which are inserted into said sleeveare triangular in cross-section.
 7. A positioning device as claimed inclaim 6 wherein said opening in said sleeve is of quadraticcross-section.
 8. A positioning device as claimed in claim 6 whereinsaid rods include respective further portions extending outside saidsleeve which are of quadratic cross-section.
 9. A positioning device asclaimed in claim 1 wherein said first and second surfaces of each rodare at right angles to one another.
 10. A positioning device as claimedin claim 1 wherein said third surfaces of said rods extend parallel tothe respective edges of said rods.
 11. A positioning device as claimedin claim 2 wherein said polygonal cross-section of each rod is anisosceles right triangle.
 12. A positioning device as claimed in claim 1wherein the sum of the angles formed between the first and second flatsurfaces of the rods is equal to 360°.